Although the fact that small validation
sets limit the ability for model selection has been discussed in [1]}, the work presented in [2]} has used the Hoeffding inequality [3]} to directly analyze the relationship between the size of validation set and the variance in estimation of a
model’s accuracy:
\(\mathbb {P}(|\overline{V}-\mathbb {E}(V)|<p)>1-2 \textit { exp}(-2np^2).\) 
